Mechanically operated pencil with screw feed



Dec. l2, 1950 G. H. wElNBl-:RGER

MECHANICALLY OPERATED PENCIL WITH SCREW FEED Filed Feb. 4, 1948 VThisinvention relates Patented Dec. 12, 1950 MECHANICALLY OPERATED PENCILWITH SCREW FEED George Hugo Weinberger, London, England, as-

signor to Henry Weinberger Limited, London, England, a British companyApplication February 4, 1948, Serial No. 6,147 In Great Britain November29, 1943 section 1, Public Law 690, August s, 1946 Patent expiresNovember 29, 1963v l to mechanically operated The object oi theinvention is the pro The inpencils. lvision of improvements in suchpencils.

`vention consists broadly of a mechanically operated pencil comprising aiiXed tubular hub with a longitudinal slot through its wall, a tubeformed with a helical slot, said helix surrounding said yhub and beingcapable of rotary movement but being substantially xed in. respect oflongitudinal movement on said hub, a stick for propelling the leadlocated within said hub, a lateral projection extending from said stickand passing through said longitudinal slot in said hub, a helicalportion extending from said lateral projection outside said hub, saidhelical portion lying. within the helical slot of said tube, wherebyrotation of said tube causes said .helical portion, and therefore saidstick to move longitudinally in said hub, means whereby, as said stickapproaches one end of its stroke, said helical portion is pro-igressively screwed out of the corresponding end of said helical slot,and stop means whereby said helical portion during such progressivescrewingout is stopped so that continued screwing-out causes saidhelical portion to be compressed in the manner of a spring until saidhelical portion is screwed completely out of said helical slot,whereuponv continued rotation of said tube can be effected withoutdamage, the compression of said helical portion ensuring its re-entryinto said helical slot upon rotation of said tube in the oppositedirection.

This arrangement also assures smooth working by spreading the drive overthe leading edge of the helical portion, instead of the drive dependingsolely on a pin formed by bending up the stick through the tube slot.

In order that the invention may be the more clearly understood amechanically operated pencil in accordance therewith will now bedescribed, reference being made to the accompanying drawings wherein-Figure l is a longitudinal section of said pencil with the stick andlead-holder in the fully retracted position;

Figure 2 is a side elevation of the tube together with the stick andlead-holder;

Figure 3 is a side elevatio-n of the stick, indicating the manner inwhich the lateral projection thereof is formed;

Figure 4 is a similar view to Figure l with the stick and lead-holder inthe fully forward position, the stick having moved forwardly relative tothe lead-holder for expelling the lead;

7 Claims. (Cl. 1Z0-'18) Figure 5 is a similar view to Figure 1 of the,butt end. of the pencil, illustrating a modification,

Referring first to Figure l to 4, the mechanically operated pencilcomprises the usual point element l having rigidly aiiixed to it andextendingA rearwardly from it a standard tubular hub 2. This hub 2 has.located in it the so-called stick 3 which propels the lead 4, and thepropulsion of the stick is effected by virtue of the rear end thereofprojecting laterally through a longitudinal slot 2a in the hub, and intoa spiral slot a inthe wall of a tube 5 surrounding the-'hub androtatable thereonbut substantially iixed in relation to` axial movement.This last named tube 5 is usually termed the helix. The stick 3 has atubular lead-holder 6 mounted on,v itf'an'd projecting forwardly fromit, and,l in the usual way, the sti-ck together with the lead-holder 'ispropelled forwardly or` rearwardly accordingto the direction of rotationof the helix 5, and the lead Il is accordingly pushed outof, orwithdrawn into, the point element I.

Mounted rigidly on the outside of the forward end of the helix is ashort tubular' member '1 with a. knurled outside surface, known 'as theknurled bush, by which the helix'is rotated rela.- tive to' the pointelement l and the hub'2. This bush 'lV extends'iorwardly beyond theforward end of the helix 5 and at itsforward end engages in an annularvrecess la inthe rear end of the point element l as shown. Thisengagement-of the bush 'l with the point element I forms the means forpreventing -the `heli-x 5- from moving forwardly relative to the hub-2.To prevent'said helix 5 from moving rearwardly lrelativeto the hub 2,said hubhas a stop washer 8 clamped on it just beyond the rear end ofsaid helix. -The barrel il. of the .pencil ts suiiiciently tightly onthe bush 'l both for retention of said barrel in .place and for enablingsaid barrel to vrotate said bush and therefore said helix.. .l l As sofar described the construction is more or less in accordance withstandard .practice. -In the present arrangement the rear lateralprojection of the stick 3 consists of an-elongatedrpart which firstprojects at 3a at right angles from the rear end of the stick throughthe longitudinal slot 2u in the hub 2- and into the spiral slot 5a, inthe helix 5, and thenat 3b extends spirallyjorwards with .said spiralslot to the extent of,. say, a single turn or less. r

In construction the stick `3, together .with the lateral projection 3a,3b, can be made of a-single stamping of light sheet metal. Thisstamping',I

in the blank, consists of a strip forming thefstick the forward limit ofits movement.

and a strip extension from the rear end of said stick extending rlrst ashort distance as at 3a at right angles to said'stick, and -then turningat an inclined angle forwardly as indicated in chain dotted lines inFigure 3. The forwardly inclined portion is at the correct angle suchthat by placing the stick within the hub 2r with the short right-angleportion 3a passing through the slot 2a in the hub and into the slot 5ain the helix 5, and by simply wrappingv the inclined portion round thehub, said inclined portion will assume the correct spiral shape as 3b tot in the slot 5a of the helix `as stated. f

rIhe spiral portion 3b extending forwardly from the right-angle portion3U, forms a spring, and when the stick 3 is screwed forwardly towardsits limit, the forward end of this spring abuts against the forward endof the aforesaid annular recess la in the rear of the point element.When the stick is then screwed still further forwards, this springcompresses as shown in Figure ll, until the right-angled portion 3a andthe stick 3 itself "are screwed right out of the spiral slot 5a, and

the helix can then continue turning without any ,part Vbeingoverstrained, the right-angled portion Viler being kept pressed againstthe front end vof the helixv 5 by the spring 3b. The stick 3 is now atAs soon as the helix 5 is turned in the reverse direction, theright-angle'portion 3a will re-engage in the spiral slot 5c and thespring `3b will expand and once `-more engage in the spiral slot and thestick 3 will "be retracted.

The original blank may be cut so that the for- 'ward extremity of thespring 3b presents an edge linfa plane at rightv angles to the axis ofthe pencil,which edge abuts flush against the end of the said annularrecess la in the point element i.

The lead-'holder makes a friction tight sliding ton the stick 3, and, inthe usual way, when the stick is screwed to' the extreme forward posi-'tion' the forward end of the lead-holder is stopped fby a-shoulder ibin the bore of the point element l and the stick. 3 continues to moveforward. l When the stick 3 is A thereby ejecting the lead 4.subsequently screwed rearwardly towards its limit,

`the`rear end of the lead-holder ii rst abuts against-an obstruction I3in the hub 2, and subsequently the lead-holder E is thereby slid fortionreaches the rear end of the slot iid further movement in the rearwarddirection is stopped.

Referring now to Figure 5, this illustrates a modification in which theabove described func- 5' tion of the spring tb, upon the stick 3 beingactuated to the forward limit of its travel also takes place upon saidstick being actuated to the rear limit of its travel.

To this end the tubular bush 'i is increased in length and arranged asshown so that it extends rearwardly beyond the rear end of the helix 5,and the bore of the barrel 9 is enlarged for the accommodation of saidbush. In the arrangement shown the rear end of said bush 'L' is closedby means of a ring i8. The hub 2 is extended rearwardly through acentral opening in the ring Nl and the rear end of said hub is closed bymeans Aof a screw i l which' also' holds the ring loin place. Theslot-2a in said hub 2 (not designated `in Figure 5) terminates at itsrear end about lush with the forward surface of the ring I0. Theleadvholder-S at the rear end of its travel, abuts against saidv screw ii and the slot 6a in said lead-holder (not designated in Figure 5) iscontinued to the rear extremity of said lead holder. The reference I2designates a rear end closure piece for the barrel 9.

From the above it will be seen that as the stick 3 approachesv the rearend of its travel, rst the rear end ofthe lead-holder i6 will abutagainst the screw I3, whereupon continued rotation of the helix 5 in thewithdrawing direction will move the stick back without the lead-holderand thus restore the stick and lead-holder to the correct relativeposition for receiving the lead. When this lcorrect relative position isattained, the portiond of the stick unit will abut against the ring il)and further rearward movement of the stick willaccordingly be prevented.Continued rotation of the helix 5 in the withdrawing direction will nowprogressively screw the spring Yportion 3b out of the helical slot `5aand said spring portion will be progressively compressed until theposition illustrated in Figure 5 is reached at which said spring portionis completely outside said. helical slot.

Continued rotation of the helix E inthe withdrawing direction will thensimply cause the rearward edge of the said helix to slide ovel theforward end of said spring portion 3b, and no harm can be inflicted onany of the parts however long this withdrawing rotation is continued.

,When the helix isnow rotated inthe lead-projecting direction, the firsttime the'rear end of the slot 5a registers with theforward end of thespring'portion said forward end of said spring portion 3b will entersaid slot, and, as rotation of the helix in the forward direction iscontinued, said spring portion will progressively enter said slot'untilthe whole of it, including the portion 3a. is in said' slot, whereuponcontinued rotation of said helix in the projecting direction will propelthe stick 3 forwardly as heretofore. v

It will be appreciated that, in either embodinient of the invention thespring portion 3b is not necessarily made in one integral piece with thestick, but could consist of an ordinary spring of' the correct pitchattached to the stick.

We are aware that arrnechanically operated pencil has been heretoforekproposed comprising a fixed gland of square section,A a carrier tubefor'the lead Yhaving a^part of square section whereby Vit islongitudinally slidable but not rotatable in said gland, aw'irelead-electing ele- Arnent for propelling the lead located in saidcarrier tube, a lateral projection extending from said lead-eiectingelement and passing through a longitudinal slot in` said carrier tube, ahelical wire spring extending from said lateral projection outside saidcarrier tube and having its end remote from said lead-ejecting elementsecured to said carrier tube, an yoperating tube surrounding said wirespring and Aformed with a helical groove in which said wire springengages, said operating tube being capable of rotary but not-substantiallongitudinal movement. whereby rotation of said operating tube causessaid wire spring. and therefore said lead-eiecting element and carriertube to move longitudinally, means whereby, as said lead-ejectingelement approaches one end of its Stroke said wire spring isprogressively screwed out of the corresponding end of said helicalgroove, .and stop means whereby said wire spring, during 's'uchprogressive Ascrewing-out, is stopped,

answer so that continued screwing-out causes said wire spring to becompressed until it is screwed completely out of said helical groove,whereupon continued rotation of said operating tube can be effectedwithout damage, the compression of said wire spring ensuring itsre-entry into said helical groove upon rotation of said operating tubein the opposite' direction.

I claim:

1. A mechanically operated pencil comprising a point portion formed withan axial hole through which the lead is adapted to be projected, atubular hub secured coaxially to said point portion and extendingrearwardly therefrom, saidl tubular hub having a longitudinal slotthrough its wall, a tube formed with a helical slot surrounding saidhub, a tubular bush surrounding saidl tube and fixed thereto, said bushextending forwardly beyond the forward end of said tube, forwardlongitudinal movement of Vsaid tube relative to said hub being preventedby abutment of said bush against said point portion, stop meansmounted'on said hub for preventing rearward 1ongitudinal movement 0fsaid tube relative to said hub, a stick, for propelling the lead,located within said hub, a lateral projection extending from said stickand passing through said longitudinal slot in said hub, and a helicalportionlextending from said lateral projection outside said hub, saidhelical portion lying within the helicallot of said tube, wherebyrotation of said tubegrelative to said hub causes said helicalportion,.and therefore said stick, to move longitudinally in said hub,said helical portion, as the stickfapproaches the forward end of itsstroke being adapted to be progressively screwed out of the forward endof said helical slot, and being adapted, during such progressivescrewing out to be compressed against said point portion (in the mannerof a spring) until it is screwed `completely lout of said helical slot,whereupon continued rotationof said tube relative to said hub can beeffected without darnage, the compression of said helicalsportionensuring its re-entry into said helical slot upon rotation of said tubein the opposite direction.

2. A mechanically operated pencil comprising a point portion formed withan axialy hole through which the lead is adapted to be projected, atubular hub secured coaxially to said point portion and extendingrearwardly therefrom, said tubular hub having a longitudinal slotthroughits wall, a tube formed with a helical slot surround-- ing saidhub, tubular bush means surrounding said tube and xed thereto, said bushmeans extending both forwardly beyond theforward end and rearwardlybeyond the rear endfof said tube, stop means mounted on said hub at therear end, forward longitudinal movement of said tube relative to saidhub being prevented by abutment of said bush means against said pointportion and rearward longitudinal movement of said tube relative to saidhub beingy prevented by abutment of said bush means against said stopmeans, stick, for propelling the lead, located within said hub, alateral projection extending from said stick and passing through saidlongitudinal slot in said hub and a helical portion extending from saidlateral projection outside sai'dhub, said helical portion lying withinthe helical slot of said tube, whereby rotation of said tube relative tosaid hub causes said helical portion, and therefore said stick, to movelongitudinally in said hub, said helical portion, as the stickapproaches either end of its stroke being adapted to be. progressivelyscrewed out of the corresponding end of said heli- 3. A mechanicallyoperated pencil comprising a tubular hub having a longitudinal slotthrough its wall, a tube formed with a helical slot surrounding saidhub, stop means mounted on said tube at a radius different from that ofthe wall of Said tube and abutting against corresponding stop meanswhich are fixed relative to said hub for preventing movement of saidtube relative to said hub in one direction, stop means fixed relative tosaid hub for preventing movement of said tube relative to said hub in'the other direction, means xed relative to said hub providing a stopsurface which istat the same radius as the wall of said hub and isspaced beyond the extremity of said hub in the rst named direction, astick, for propelling the lead, located within said hub, a lateralprojection extending from said stick and passing through saidlongitudinal slot in said hub and a helical portion extending from saidlateral projection outside said hub, said helical portion lying withinthe helical slot of Said tube, whereby rotation of said tube relative tosaid hub causes said helical portion, and therefore said stick, to movelongitudinally in said hub, said helical portion, as the stickapproaches the end of its stroke in the rst named direction beingadapted to be progressively screwed out of the corresponding end of saidhelical slot and being adapted, during such progressive screwing out, tobe compressed against said stop surface in the manner of a spring untilit is screwed completely out of said helical slot, whereupon continuedrotation of said tube relative to said hub can be effected withoutdamage, the compression of said helical portion ensuring its re-entryinto said helical slot upon rotation of said tube in the opposite direction.

li. A mechanically operated pencil comprising a tubular hub having alongitudinal slot through its wall, a tube formed with a helical slotsurrounding said hub, stop means mounted on said tube at a radiusdifferent from that of the wall of said tube and abutting againstcorresponding forward lstop means which are xed relative to said hub,for preventing forward movement of said tube relative to said hub, stopmeans mounted on said tube at a radius different from that of the wallof said tube and abutting against corresponding rear stop means whichare fixed relative to Said hub, for preventing rear movement of saidtube relative to said hub, means fixed relative to said hub providing aforward stop surface which is at thecsame radius as the wall of said huband is spaced forwardly beyond the forward extremity of said hub, meansfixed relative to said hub providing a rear stop surface which is at thesame radius as the wall of said hub and is spaced rearwardly beyond therear extremity of said hub, a stick, for propelling the lead, locatedwithin said hub, a lateral projection extending from said stick andpassing through said longitudinal slot in said hub, and a helicalportion extending fromlsaid lateral projection outside said hub, saidhelical portion lying within esteem@ theehelicalislotpoffsaid itube,whereby rotation ofi said tube -relativeto said hub causes.saidhelical'-,

portionv and thereforesaidstick, to lmovelongi#` tudinally in said hub,said helical portion, `as the stick approacheseither endofits.-strokeloeing adapted to be progressively screwed out of, thecorresponding end xof said helical slot, and=being adapted; vduringgsuchprogressive screwing outto bet'compressed. againstV said forward orl:rea-r; stop, surface; asfthe case maybe,v in the manner ofA av springuntil it is screwed completelyoutof said;

helical slot, whereuponfcontinued rotation of said tubefrelative toAsaidA hubv can ,be eifectedwthout damage; thecornpression-of saidyhelical portion ensuringitsfre-entry-r into rsaid helicahslot upon;

meansl iixed relative to said hub, providing av stop surface whiclfrn isat,I the same radius` as. thewall'of said. huband is spaced. beyondtheextremityof said hub in the rstnamed direc-- tion, al stick-forpropellingr the .lead;` at, lateral' projection extendingfrom said'stick and...passf ingthrough said longitudinalrslot infsaidhub, andahelical portion extending-from-said lateral.

projection outside said hub, said,Y helical portion lying within .the,helical slot of 'said tube,whereby rotation of. said tuberelative to.said hub causes said helical portion. andv therefore said` stick, ,to

move longitudinally in vvsaidhub, saidstick, said.

lateral projection and ,saidhelicaliportionbeing.

formed of. one integral stamping `of sheet metal; saidhelical portionasthe. stickapproaches the end,A ofA its stroke -in the. iirst` nameddirection being adapted to be progressively screwedoutof thecorresponding end of saidhelicallslot and being adapted, during such fprogressivascrewing out, to be compressed against said stop surface inthe mannerof a springruntil it isscrewedcom..

pletely: outoisaid helical slot, whereuponom f tinued ,rotation :of`said. tube. relative :to` saidlhub' can beefected withoutdarnage, the:compression oi said helical portion ,ensuringits re-entry intosaidrhelical. slot upon rotation ofsaidltubein.

theoppesite,direction` 6; A. mechanically, operatedY pencil comprisingaatubular hub having arlongitudinalslot`- through itsswall, a tube.formed with alhelical slotsur.-

rounding saidihub, a bush;surroundinggsaid'tube andiiixed thereto .andprojectingv beyond one end` ofi saidu tube, stop 4means iixed relativevto., said hub, thefprojecting.. extremity of saidbush abutting againstsaid stop `Ineansior preventingmove.- ment, of saidtube relative to.-saidhub fin one'dilrection, stcpmeansxed. relativeto said hubforv ipreventing movement of Isaid tube relative ;to. said hubin the, otherdirection, a` stick, lfor; propelling thel'ead, y located within ,saidhub, a lateral` pro;- jectionVA extending from said stick and passing8'; through,said ...longitudinaislot in ,saidhub and a helicalp'ortionextending from said'l'ateral progr jectionyout'side saidhub, saidhelical portion ly.-

ing within the .helical slot of said'tube, whereby tion, as the stickapproaches the end of its strokev in the first named direction beingadapted 4to,.be screwed out of the corresponding end ofsaid'helicalslot,v and being adapted during such progressive screwingout to bei compressed against saidv rst'named stop means in the mannerof'a spring until it isscrewedcompletely out of said helical slot,whereuponlcontinued rotation of, said tube relativetosad'hub can beeiiected withoutdamage, the-compression ofsaid helical portion'en'-suring'dits refentry into said helical slot upon'ro- 'tation of saidtubein the opposite direction.

i 7; A mechanically operated pencil cornprisingaI tubular-hub having alongitudinal slot through its wall, a tube formed with a helicalslot-'surrounding said hub, a-bush surrounding-said tube and fixedthereto and projecting beyond one end of'jsaid tube, stop means iixedrelative, tosaid hub, theprojecting extremity of said bush'abuttingagainst said stop means for preventing movement'of said tube relative tosaidhub in one direction, stop means fixed relative'to saidihubior`preventing movement of said tube relative tosaid hub inthe-otherdirection, a stick for propelling thefleadflocated withinsaid`hub, a lateral pro"- jection .extendingfrom said stick and passingthrough said longitudinal' slot in saidhub, anda helical `portionlextendingfrom said lateral projeetionoutside saidV hub, said helicalportion lyingwithinxthe helical slot of saidtube whereby rotation4of'said tube lrelative to said hub, causes said" helical portion; andthereforeV said stick; to move longitudinallyinsaid hub, said helicalportionas the stick approaches the end of-'its strokeinitherstinameddirection being adapted tosbe screwed'outof'thezcorresponding end of said hel'- ical slot,l and being adaptedduring lsuch progressiveu screwing'out to be comp'ressed'against saidfirst named stoprmeans'i'n themanner-of a'spring until it..is screwed'completely out'of'said helical slot whereupon continued rotationV ofsaid tube relative to said'hub can .be effected without-damage; thecompression of said helicalportionxen'- suring its reeentry into` saidhelical slot upon ro;- tationofsaid tubey in thn opposite direction; apencilv point portion inxed relation to said hub, and'apencil barrelportion surrounding said'bush iniriction-tight relation;

GEORGE HUGOA WEINBERGER:

REFERENCES CITED yThe.followingreferences*are ofrecord in thel fileofthis patent;

UNITED STATES PATENTS Number Name Date 1,496,163" DOlierv J une` 1924'FOREIGN l PAWNTASL Numbery Country Datef 56937451 Great Britain J une 6g' 1945

